I'm not sure if I'm missing something, but I'm wondering about the sorting in Play for multi-disc collections.

I have a collection where the metadata for each track includes the number of disc within the total number of discs. When I open the library window and sort by track, the tracks are sorted by 1/9,1/10, etc. This seems a little random to me. What I would expect is all tracks sorted by disc number first, then track number within that disc. Am I missing an option here?

Note: I'm using the unstable version of Play. Could that have something to do with it?